BEHAVIOR ACROSS THE MENSTRUAL CYCLE IN SOOTY MANGABEYS (CERCOCEBUS ATYS)

We are investigating a breeding management protocol to increase genetic diversity in the sooty mangabey colony at the Yerkes National Primate Research Center. One concern is that females who temporarily leave their groups for breeding will face increased aggression when they return. To assess this accurately, we need to determine whether changes across the menstrual cycle affect rates of aggressive interactions in females. Studies on behavior across the cycle in other nonhuman primates report conflicting conclusions. Here, we monitored the frequency and duration of aggressive, prosocial, and sexual interactions in eight adult female mangabeys at four stages in their cycles (stages 1 and 2 corresponded with minimum perineal swelling size and menses; stages 3 and 4 corresponded with maximum size and ovulation). We recorded 247 hours using focal animal sampling (5-9 hours per subject, per stage). A MANOVA showed that the frequency and duration of aggressive and prosocial interactions did not change as a function of cycle stage (F(12, 32)=1.33; p=0.25). However, as in macaques and chimpanzees, posthoc pairwise comparisons showed that sexual interactions were significantly higher when subjects were in stage 4 (p<0.02). The lack of change in aggressive interactions across the cycle will allow us to accurately identify potential aggression resulting from the removal and reintroduction of select females for breeding purposes and to evaluate the practicality and efficacy of this management practice.